Acta Pharmacologica Sinica 2006 February; 27 (2): 212-216; doi: 10.1111/j.1745-7254.2006.00266.x

Acta Pharmacologica Sinica 2006 February; 27 (2): 212-216; doi: 10.1111/j.1745-7254.2006.00266.x

Original Article

Effects of orexins on myoelectric activity of sphincter of Oddi in fasted rabbits¹

Song-tao LI^2,4, Xiao-wei CHEN^2,3,4, Hong-mei ZHAO², Na LI², Jie YAN², Zhi-an HU^2,3,5

²Experimental Center of Basic Medicine and ³Department of Neurobiology, Third Military Medical University, Chongqing 400038, China

Aim: To investigate the effects of peripheral orexins on myoelectric activity of the sphincter of Oddi (SO) in fasted rabbits, and carry out a preliminary investigation into the mechanisms underlying these effects.

Methods: Myoelectric activity of SO in fasted rabbits was recorded before and after intravenous or local application of orexins. The effects of intravenous atropine on orexin-increased myoelectric activity of SO were tested.

Results: Myoelectric activity of SO was activated by both intravenous and local injection of orexin-A or orexin-B. Intravenous application of atropine completely inhibited the excitatory effect of orexins on SO.

Conclusion: Peripheral application of orexins can increase myoelectric activity of SO in fasted rabbits, which is partially associated with the activation of the cholinergic pathway.

Keywords: sphincter of Oddi; orexins; myoelectric activity; spike potential; rabbits

¹Project supported by the National Natural Science Foundation of China (No 30370465).
⁴ These authors contributed equally to this work.⁵Correspondence to Prof Zhi-an HU.
Phn/Fax 86-23-6875-3704.
E-mail zhianhu@yahoo.com.cn
Received 2005-07-04 Accepted 2005-10-31

[ Full text ]